I know some have already addressed this issue artistically, but I want to voice some thoughts about Sesshomaru and his "adoption" of Rin.
The adoption of the waif Rin by the uber-InuYoukai Sesshomaru was without a doubt, a real head-scratcher. What was it all about anyway? Well, I think that it was likely not much more than what it was on the surface, really. Meaning, I think that he adopted Rin after he invested some rare emotions in her. He was surprised that she would go through so much to take care of him in his time of need, even when he tried to drive her away. And when she chose to follow him on his travels, he looked after her,